Wireless communication typically involves the transmission of information between a subscriber terminal 200, such as a cellular telephone or pager, and a cell station or base station. In such a communication system, the subscriber terminal 200 utilizes radio-frequencies ("rf") to communicate with relatively low-powered and limited-radiation coverage cell stations arranged in a cellular pattern. As a result, the wireless communication systems of this type are prone to call failures caused by bad coverage areas in the rf communications link.
In an indoor wireless system, there are number of sources of interference which may be encountered. For instance, for systems transmitting in the industrial and scientific band, around 2.4 GHz, interference may arise from other sources within the same band, like microwave ovens and security systems. For systems transmitting in the narrowband personal communication services, between 900 and 950 MHz, interference may be caused by barcode readers and child monitoring systems. For cordless telephones in 47 MHz band, random radio signals from other phones lead to spontaneous ringing and squawking noises. These interferences will eventually lead to undesirable link failures. In addition, coverage can be interrupted by rf shields, such as metal walls.
Determining the exact cause of such failure is often difficult as rf propagation characteristics vary greatly within a building. Predicting optimum cell station placement to prevent such problems has proven difficult. Predicting post-installation building modifications and user traffic patterns is similarly problematic. It has been suggested that an installation provide user problem reporting system. However, in practice, it has been found that users either provide unreliable information regarding rf coverage or neglect to accurately record failure conditions.